Expansible reveal with frontal tear strip for plaster walls

ABSTRACT

An extruded generally T-shaped separator or screed is tacked along the wall base with the center leg projecting outwardly. Plaster is applied to the wall base to interlock opposite sides of the screed leg. The screed leg is itself hollow, the frontal exposed side being a tear strip finally removed to form a reveal, and the rearward side being bowed or sinuous to form an expansion mechanism. As the plaster expands and contracts transversely to the screed leg, the reveal opens and closes correspondingly without any separation of the leg sides from the respective sections of the cast wall.

United States Patent Arnett 15] 3,667,174 [451 June 6, 1972 54]EXPANSIBLE REVEAL WITH FRONTAL TEAR STRIP FOR PLASTER WALLS [72]Inventor: Robert W. Arnett,

Pasadena, Calif. 91 105 22 Filed: Feb. 13, 1970 21 Appl.No.: 11,206

1030 Stoneridge,

[52] US. Cl ..52/l00, 52/256, 52/257, 52/364, 52/709, 52/710 [51] Int.Cl ..E04b 1/41 [58] Field of Search ..52/58, 60, 61,100, 212, 364,52/371, 377, 399, 255-257, 709, 710

[56] References Cited UNITED STATES PATENTS 1,386,509 8/1921 Kinnes etal ..52/7l0 1,204,955 11/1916 Day ....52/364 3,015,194 1/1962 Clark......52/371 3,192,557 7/1965 Barn... ....52/364 3,319,384 5/1967 Berg..52/6l 3,319,985 5/1967 Amett ..52/204 Buh1er..... ..52/7l0 3,387,4196/1968 Karnberg et al. ...52/255 3,512,318 5/1970 Turner ,.52/lO0FOREIGN PATENTS QR APPLICATIONS 1,333,580 6/1963 France ..52/710 PrimaryExaminer-Frank L. Abbott Assistant ExaminerLeslie A. Braun Att0rneyFlamand Flam [57] ABSTRACT An extruded generally T-shaped separator orscreed is tacked along the wall base with' the center leg projectingoutwardly. Plaster is applied to the wall base to interlock oppositesides of the screed leg. The screed leg is itself hollow, the frontalexposed side being a tear strip finally removed to form a reveal, andthe rearward side being bowed or sinuous to form an expansion mechanism.As the plaster expands and contracts transversely to the screed leg, thereveal opens and closes correspondingly without any separation of theleg sides from the respective sections of the cast wall.

1 Clairrs, 4 Drawing Figures EXPANSIBLE REVEAL WITH FRONTAL TEAR STRIPFOR PLASTER WALLS BACKGROUND OF THE INVENTION 1. Field of Invention Thisinvention relates to wall construction, and more particularly, to ascreed forming a decorative expansible reveal between adjoining sectionsof a plaster or other cast wall.

2. Discussion of Prior Art For a variety of reasons, plaster and othercast walls expand and contract to a considerable degree long after thecast wall is cured. A chronic cause is temperature change. Another causein high structures is flexure due to wind loading. Seismic disturbancesare acute causes. Irregular cracks can be minimized by dividing the castwall into sections as by the use of divider members such as a strip or achannel. But in this instance, an unsightly slit may open between theside of the divider member itself and the side edge of the cast wall.Expansion of the cast wall may not be properly tolerated by suchseparator strips.

A neat joint between the side of the divider member and the abuttingsurface of the cast material is difficult to achieve. The plaster orother material tends to splash over the divider member.

To achieve a neat finished appearance when a solid strip is used as thedivider member, the divider member should be wiped clean before thesplashed over material cures, because removal after curing results inpulling away patches of the plaster on the finish side. This, of course,is tedious and thus economically unsound.

If a channel is used as the divider member, sharp edges at the channelsides may provide a sufficient discontinuity to prevent any bondedjuncture between the splashed over material and the plaster on thefinish side. However, the channel will have to be cleaned later withconsequent penalty as to Cost.

Another solution is to apply masking tape over the solid separator orchannel separator. This usually results in pulling patches of materialfrom the finished side. Applying the tape is also time consuming.

BRIEF SUMMARY OF THE INVENTION v The primary object of this invention isto provide a simple screed that forms a decorative expansible revealfree of the foregoing disadvantages. For this purpose, I provide anextruded separator or screed of hollow generally rectangularconfiguration. The front wall is joined to the side walls by thinfracture webs. The webs are so located as to form small sharp V-grooves,the webs being located at the troughs of the grooves with the side edgesof the front wall forming the inner sides of the V-grooves and the sidewalls of the screed forming the outer sides of the V-grooves. The frontwall forms a tear strip removed after the plaster is set. A clean revealremains. Any splashed over plaster entering the V-grooves is neatlybroken away as the tear strip is removed. Attaching flanges form lateralextensions of the rear wall of the screed. The rear wall is curved,sinuous, or otherwise non-linearly formed to allow the side walls tomove toward and away from each other as the cast wall expands andcontracts.

BRIEF DESCRIPTION OF THE DRAMNGS A detailed description of the inventionwill be made with reference to the accompanying drawings. Thesedrawings, unless described as diagrammatic or unless otherwiseindicated, are to scale.

FIG. 1 is a pictorial view of a length of an extruded separator orscreed incorporating the present invention.

FIG. 2 is a view similar to FIG. 1 but showing the separator installed.

FIG. 3 is a sectional view taken along a plane corresponding to line 3-3of FIG. 2.

FIG. 4 is a sectional view similar to FIG. 3 but illustrating aseparator having a difierent reveal size.

DETAILED DESCRIPTION The following detailed description is of the bestpresently contemplated modes of carrying out the invention. Thisdescription is not to be taken in a limiting sense, but is made merelyfor the purpose of illustrating the general principles of the inventionsince the scope of the invention is best defined by the appended claims.Structural and operational characteristics attributed to fonns of theinvention first described shall also be attributed to forms laterdescribed, unless such characteristics are obviously inapplicable orunless specific exception is made.

The separator or screed shown in FIG. 1 is a one-piece extrusion ofgenerally T-shaped configuration. A wide variety of plastics or othermaterials may be used. Preferably the plastic is flexible and softenough to permit it to be'readily cut to length and to be nailed inplace. Polyvinyl chloride fulfills the requirements.

The center leg of the T-shaped separator is itself a hollow four-sidedstructure, there being opposite parallel side walls 10 and 12, a frontwall 14 and a rear wall 16. Extending laterally from the comers at therear wall are attaching flanges 18 and 20. These flanges may be tackedto the lath W or other wall base upon which plaster or other cementiousmaterial is intended to be cast. Holes 24 for the tacks may be providedif desired.

The side walls 10 and 12 are designed to form edging for the opposedends of the plaster slabs or wall sections A and B cast on the wall W.The outer ends of the side walls 10 and 12 are inwardly beveled as at 22and 23 so that the ends of the walls 10 and 12 terminate at sharp edges.The ends of the front wall 14 are similarly inwardly beveled as at 26and 28. Accordingly, frontally facing shallow V-shaped grooves 30 and 32are formed.

The front wall 14 is substantially flush with the edges of the sidewalls. The thickness of the front wall 14 only very slightly exceeds thedepth of the V-grooves 30 and 32; the front wall is thus joined to theside walls 10 and 12 only by a thin fracture web.

The wet plaster is applied to the wall W with a thickness equal to thedimension of the separator side walls 10 and 12. The separator forms aground along or across which a feather edge may be moved. Laterallyextending interlock flanges 36 and 38 extend outwardly from the sidewalls 10 and 12 to provide a firm connection.

Some of the plaster material may enter the V-grooves 30 and 32. Thisexcess will then be joined, if at all, to the main body of the plastersections A and B only by an extremely thin readily frangible web. Afterthe plaster is set, the front wall 14 is torn away as indicated by thearrow 40 (FIG. 2). Any material in the V-grooves 30 and 32 is clearlycarried away with the tear strip or front wall 14. A neat, clean revealaccordingly remains.

Upon expansion and contraction of the slabs A and B, the side walls 10and 12 move correspondingly, being anchored to the respective slabs bythe T-head interlock flanges 36 and 38. This movement further is ensuredby the inwardly arched configuration of the rear wall 16. No unsightlycrack develops between the side walls 10 and 12 and the correspondingsurfaces of the plaster material.

In the form shown in FIG. 4 a similar arrangement is provided in whichthe screed has different proportions. In this instance, the reveal iswider. Hence, the degree of bowing of the rear wall need not be so greatto allow the same expansion.

I claim:

1. In a wall structure including a support and a pair of separate slabsof plaster-like material cast in situ on said support, the combinationtherewith of a unitary elongated expansible hollow separator betweensaid slabs:

a. said separator having a front wall, a rear wall and opposite sidewalls;

b. said rear wall including a pair of planar flanges for attaching saidseparator to said support with said front wall facing outwardly, saidflanges respectively extending slabs'are formed, said fracture websbeing defined by inwardly beveled outer ends of said side walls, saidfront wall being substantially flush with said side wall outer edges sothat upon removal of said front wall said separator is exposed only atthe region of its hollow interior; and

. each said side wall being provided with an anchor means disposedintermediate said front and rear walls and extending laterally outwardlyfrom that side wall, the outer end of each anchor being a T-head lockingthe side wall to its associated slab for conjoint movement therewith.

1. In a wall structure including a support and a pair of separate slabsof plaster-like material cast in situ on said support, the combinationtherewith of a unitary elongated expansible hollow separator betweensaid slabs: a. said separator having a front wall, a rear wall andopposite side walls; b. said rear wall including a pair of planarflanges for attaching said separator to said support with said frontwall facing outwardly, said flanges respectively extending laterally inopposite directions, said side walls serving as screeds to establish thethickness of said slabs; c. the center portion of said rear wall beinginwardly arched to allow movement of said side walls toward and awayfrom each other in response to expansion and contraction of saidseparate slabs; d. said front wall being joined to the side walls byfracture webs of thinner cross-section than said front wall whereby saidfront wall forms a tear strip removable after said slabs are formed,said fracture webs being defined by inwardly beveled outer ends of saidside walls, said front wall being substantially flush with said sidewall outer edges so that upon removal of said front wall said separatoris exposed only at the region of its hollow interior; and e. each saidside wall being provided with an anchor means disposed intermediate saidfront and rear walls and extending laterally outwardly from that sidewall, the outer end of each anchor being a T-head locking the side wallto its associated slab for conjoint movement therewith.